MULTI-FEED WEAVING LOOM, A WEAVING METHOD USING SUCH A WEAVING LOOM AND AN APERTURED FABRIC OBTAINED THEREBY

Abstract

A weaving loom includes a system for inserting weft threads in a plurality of layers and a system for inserting and sequencing warp threads in such a way as to produce a multilayer fabric having a defined weave. It includes at least two feed systems of which the speed and traction force are controlled such that, at least locally, one portion of the layers of fabric is driven by the feed mechanism of same at a different speed to at least one other portion of the layers of multilayer fabric so as to produce at least one aperture on the multilayer fabric.

Description

FIELD

The present disclosure relates to a multi-feed weaving loom. It concerns a weaving method using such a weaving loom and an apertured fabric obtained thereby. It finds application in particular in the field of realizing fabric preforms for composite parts including at least one aperture.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

In the state of the art, a group of layers of the multi-layer fabric constitutes an aperture which thus forms a projection above the multi-layer fabric itself. A kind of tunnel is thus formed in the weft direction.

According to a first known technique, the weaving is carried out in a traditional manner of two parallel fabrics. Then the debonding of the fabrics is carried out to form a tube and finally the bonding of the desired edges of the tube is carried out.

According to a second technique, a surplus length of fabric is realized by keeping yarns which do not work during the weaving the surplus length. Using a reed which returns backwards, the fabric is brought back to the base of the tube so as to form a loop.

According to a third technique, the stitch weaving technique is used. But instead of varying the movement stroke of the reed, a negative feed is carried out by bringing back the fabric to the base of the loop.

Such fabrics are usable to realize preforms only if additional shaping and consolidation operations comprising draping and stitching are then applied to them.

In the document U.S. Pat. No. 3,207,185, there is described a method for realizing a fabric preform presenting two parallel and debonded layers, but then bonded to each other by one or several pair(s) of filling layers. The mechanism allows to open the weaving angle to bond one or the other of two parallel layers by a filling layer.

Yet, these techniques present drawbacks which reduce their use in realizing complex parts based on woven preforms. Particularly, in weaving in general, the warp yarns are constrained to a single feed. It is therefore possible to produce fabric tubes, but the debonding of which does not allow to produce a very long loop above and/or below a fabric layer of smaller length.

In the stitch weaving, the maximum admissible length is limited by the stroke of the reed, which restricts the ratio between the longest length of a group of fabric layers and the shortest length of the other layers. The stitch does not allow either to resume a loop on another loop.

When the fabric tube must be realized by resorting to a negative feed, the only wrap yarns which are not part of the longest loop should be swallowed and this operation is impossible on the storage systems of the current yarns.

Finally, the necessary shaping operations with the aforementioned weavings constitute additional production operations. Thus, mechanically, there is no longer continuity of yarns therebetween and the mechanical properties of the final fabric are lesser, which is a drawback for realizing parts made from composite material such as guide or carrying rails, beams or carrier panels.

SUMMARY

The present disclosure provides a weaving loom of the kind including a system for inserting weft yarns into a plurality of layers and a system for inserting and sequencing wrap yarns so as to produce a determined multi-layer weave fabric. The loom of the present disclosure includes at least two feed systems controlled in speed and traction force so that, at least locally, a portion of the fabric layers is driven by its own feed mechanism at a different speed from at least another portion of the layers of the multi-layer fabric so as to produce at least an aperture on the multi-layer fabric.

According to other features of the present disclosure:

a feed system includes a system for gripping the multi-layer fabric and driving it at least outside the weaving periods of apertures;

at least one feed system includes a mandrel for stretching a loop which is being formed on at least one layer or group of layers of the multi-layer fabric after debonding;

the loom includes a plate reserved for the multi-layer fabric which carries a driving carriage of the feed system for gripping the multi-layer fabric and at least one plate reserved for weaving at least an aperture and which carries a driving carriage of the feed system for stretching a loop which is being formed on at least one layer or a group of layers of the multi-layer fabric after debonding;

said at least one plate reserved for weaving at least one aperture presents a determined inclination concerns the plate reserved for the weaving of the multi-layer fabric and is disposed such that the inclination is measured between the directions of the feeds of the systems respectively of said at least one weaving plate of aperture and of the weaving plate of the multi-layer fabric;

the loom includes at least one system for maintaining the position of the weaving point;

the loom includes at least one system for maintaining the position of the weaving point associated to at least one feed system for maintaining the height of the weaving point at the start of the fabric, downstream of weft yarns insertion region and a shed associated, such that the shed and the beating of the weft can be repeated to maintain height of the weaving point downstream of the insertion region of the weft yarns and the shed associated at the start of the fabric such that the shed and the beating of the weft can be repeated;

The system for maintaining the position of the weaving point includes first and second axes elongated over the thickness of the fabric on either side of the fabric surface areas downstream of the weaving point.

The features above are obtained regardless of the number, the type and the dimensions of the aperture(s).

The present disclosure also provides a weaving method using a multi-feed weaving loom according to the present disclosure. According to the present disclosure, the method includes a step for realizing the start of a multi-layer fabric under a determined feed, then a step for carrying out the debonding of at least one layer of the base fabric with stop or slow down of the feed of the weaving of the multi-layer fabric, then a step of forming a loop by overconsumption of wrap yarns and stretching under a determined feed of a determined loop length greater than that of the remaining multi-layer fabric and finally a step of closing the woven loop by bonding and resuming, if necessary, of the multi-layer weaving.

According to other features of this method:

The method is repeated along the multi-layer fabric so as to form several successive apertures; and

The method is repeated on at least one layer of at least one aperture which is being woven so as to form several inner apertures and/or several apertures of different directions.

The present disclosure also concerns a fabric obtained according to the method of the present disclosure. The apertured fabric realized according to the method is intended to realize woven preforms for manufacturing mechanical parts by injecting an injection-polymerizable material among which:

monolithic or “sandwich” type self-stiffened panels, in which the woven apertured area on the preform is used to realize a stiffener and/or a clevis and/or to include a stiffener of the hollow “Omega” or filled with foam or honeycomb structure type, a corner-flange pair, a “T” stiffener, etc.;

parts of monolithic structures as a frame of a nacelle thrust reverser of an aircraft turbojet engine, a beam, in which the area produced on the aperture(s) of the preform is calculated as a stiffener and/or as a clevis and/or composite rail; and

a part of composite material based on an apertured weaving perform and calculated for geometric and/or stiffening and/or mechanical forces passage constraints.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 represents five successive steps of the method of the present disclosure using a schematic representation of a portion of the weaving loom of the present disclosure;

FIG. 2 represents a perspective view of a portion of the weaving loom of the present disclosure according to a particular form;

FIG. 3 represents the schematic section of five fabrics realized according to the method of the present disclosure given by way of examples; and

FIGS. 4 to 7 represent successive wrap planes of an example of form of a fabric according to the present disclosure.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

In FIG. 1, successive steps of one form of the method of the present disclosure are represented. The weaving loom of the present disclosure includes the portions of a multi-layer fabric loom. It includes in particular a system for inserting weft yarn and a system for sequencing wrap yarns according to a determined weave to realize a multi-layer fabric. It weaves in a first step (a) the start of a multi-layer fabric 1. The start of the multi-layer fabric is therefore placed on a feed mechanism 4 to realize a determined feed Feed 1 of the fabric 1 with a determined traction force and a speed during its weaving and which can be stopped or slowed down by a feed controller during the carrying out of the method of the present disclosure.

The wrap yarns 2 are provided through a non-represented wrap yarns sequencing system, to form a shed inside which a weft insertion mechanism 3 circulates as it is known.

When the weaving of the aperture starts, a debonding 6 is realized between some layers of Fabric 1 (second step (b)). During the debonding, and in one form at its end, the feed mechanism 4 is disengaged so that the feed Feed 1 is stopped. In other forms, the feed Feed 1 is only slowed down so that the loop which will be formed on the upper layers will have a greater length than the lower group of layers of the debonded multi-layer fabric. In one form, the length in the direction of the feed of the weaving loom of the lower sub-group 11 of the layers of the multi-layer fabric (see step (d)) above which the loop which is being woven is drawn, is zero or almost zero.

At the third step (c), a roller or a mandrel 7 is inserted into the debonding area 6 and the roller 7 is attached to a feed mechanism 8 by bondings 9. A specific feed Feed 2 is therefore applied by the feed mechanism 8 with determined speed and traction force in particular by the tension required on the warp yarns and to provide a higher length of weaving on the loop or the aperture 10 with respect to other layers of the lower sub-group 11 on the multi-layer fabric. A loop 10 is therefore formed on the upper face of the fabric 1. The lower portion 11 of the fabric 1 is constituted of a lower sub-group of the layers of the already woven fabric 1 at the first step (a). In one form, the length in the feed direction of the weaving loom of the lower sub-group 11 is zero or almost zero. It is noted that only the wrap yarns 2 corresponding to the upper layers of the fabric, reserved for the weaving of the loop 10, are consumed. Wrap yarns 2 of the layers of the lower sub-group of the layers of the already woven fabric 1 are reserved.

In another form, the warp yarns 2 of the layers of the lower sub-group of the layers of the already woven fabric 1 are consumed at a consumption speed lower than that of the wrap yarns of the upper layers 10. As a result, the loop constituted using the upper layers 10 of the fabric presents a greater length than that of the layers of the lower sub-group. To this end, the weaving the lower sub-group 11 on the multi-layer fabric is continued simultaneously with the weaving of the loop 10. But its stretching system or feed Feed 1 works at a reduced speed with respect to the speed of the stretching system or feed Feed 2 to provide a loop 10 length greater than that of the sub-group 11 before its bonding 14.

At the fourth step (e), the loop 10 reached a desired total length. The layers reserved for the weaving of the aperture or the loop 10, 13 are therefore bonded to the lower sub-group of layers of the multi-layer fabric. Both feed mechanisms 8 and 4 pass at the same speed or the second feed mechanism 8 for the weaving of the aperture is disengaged and only the first mechanism 4 drives the multi-layer fabric. The weaving of the full multi-layer fabric resumes therefore under the effect of the feed mechanism 4 by resuming a consumption speed of wrap yarns 2 equal for all the wrap yarns of all the layers of the multi-layer fabric. It has thus been generated an aperture or pocket 13, which forms a tube the generators of which are found according to the direction of the weft and the openings on the side of the fabric webs. It is noted that the width or web of a woven aperture according to the method of the present disclosure may be different from the width or web of the base multi-layer fabric.

To resume the weaving of a multi-layer fabric downstream of the pocket or tube 10, 13, a bonding is realized between the end 14 of the upper layers 10 woven with the rest of the sub-group 11 of lower layers and the weaving a single multi-layer fabric is resumed after the bonding of the end 14. The bonding is naturally carried out by the weaving of a weave allowing to bond the layers in contact of the end of the weaving of the aperture and those of the lower sub-group 11. The operations of bonding and debonding will be explained later on an example.

In a weaving loom of the present disclosure, the first feed system reserved for the weaving of the fabric 1 itself, includes in one form two sheets 4 elongated in the direction of the weft and surrounding the thickness of the multi-layer fabric 1 on either side. The two sheets are removable to allow their mounting and their dismounting on the first end of the fabric when it is still in its first weaving area in only one multi-layer unit downstream of the not yet woven loop or aperture 10, 13. The assembling of the two sheets is screwed or otherwise secured on the end of the fabric and is bonded by a bond 5 to a driving carriage so as to apply a feed noted Feed 1 of which speed and traction force are determined depending on the multi-layer weaving and on the necessary tension of the wrap yarns 2. As it was described, the driving carriage which drives according to Feed 1 the end of the fabric is controlled by a feed controller so that Feed 1 may be reduced or canceled while maintaining if necessary a sufficient traction force when the aperture or loop 10, 13 is being woven. It is noted that a feed system of the fabric using winding mandrels of fabric conventionally used for the two-dimensional weaving is generally not recommendable because of the thickness variations. The feed system Feed 1 of the present disclosure using a principle of clamping of the end of the multi-layer fabric allows to better control the feed speed of the fabric and the traction force, even with a very thick multi-layer fabric, and with one or several aperture(s) or pocket(s) 10, 13.

In a weaving loom of the present disclosure, the second feed system reserved to the weaving of the longest loop 10, 13 includes in one form a rigid axis 7 or mandrel, which crosses the substantially entire width of the fabric 1. The rigid axis 7 is mounted on two removable traction cables 9 a first end of which is removably connected to one end of the axis 7 so as to allow its mounting and dismounting once the aperture, pocket or tube 10, 13 is woven and bonded to the rest of the fabric 1. A second end of the two traction cables of the mandrel 7 is secured to a driving carriage 8, the feed of which is controlled depending on the overconsumption of the wrap yarns 2 calculated to produce the aperture or pocket 10, 13 of determined length. The feed noted Feed 2 produced by the driving carriage 8 is also determined in feed speed and traction force by the tension necessary on the warp yarns 2.

In a weaving loom of the present disclosure using several feed systems as it has been exposed using FIG. 1, it is necessary to realize a fixation of the weaving point, whether it is found on the multi-layer fabric of complete basis, or on the weaving of the loop 10. To this end, it is disposed at least one system for maintaining the position of the weaving point. The function of maintaining the position of the weaving point is to prevent the vertical displacement of the fabric that is being woven, in particular during the weaving of a loop as the loop 10. Indeed, the drawing axis of the loop 10 by the feed system Feed 2 (FIG. 1) is offset with respect to the shed of the wrap yarns. In addition, the difference in height of the feed system Feed 2 which provides the drawing of the loop 10 with respect to the main feed system Feed 1 can engender a change in the height of the weaving point and vertically shift the shed. Such a shift can generate insertion problems of the weft yarns since the vertical position of the shed might not be controlled.

To remedy this drawback, the feed system Feed 2 disposed above the main feed system Feed 1 is equipped with a system for maintaining the position of the weaving point 70.

In the example of FIG. 1, a weaving point is constituted at the start of the fabric either on all the layers of the main fabric 1, during the step (a), at the start of the loop 10 during its own weaving in particular during the step (d) and at the start of the fabric from the bonding point 14 from the end of the loop 10 to the sub-group 11 of lower layers of the main or base fabric. The weaving point extends over the complete web or full width of the fabric in the weft direction and is preceded by a weft insertion region in which the weft insertion mechanism 3 intervenes and the opening of the shed of the wrap yarns. The system of maintaining the position of the weaving point 70 provided here for the weaving of the loop 10, therefore includes a means for maintaining the height of the weaving point at the start of the fabric. This means is disposed downstream of an insertion region of weft yarns and of a shed associated with the weaving point, such that the shed and the beating of the weft can be repeated.

In one form, the system for maintaining the position of the weaving point 70 includes two axes disposed on either side of the fabric, along the weft direction. A first axis is disposed above the weaving of the loop 10, and a second axis is disposed underneath the weaving of the loop 10. The first and second axes are extended over the entire width of the weaving of the loop 10. The first and second axes of the system for maintaining the weaving point 70 are spaced by a distance sufficient to not hinder the weaving and the drawing of the loop 10, but close enough to maintain the height of the weaving point of the loop downstream of the insertion region of the weft yarns and the shed associated with the layers reserved for the weaving of the loop 10. The two axes are thus positioned just at the start of the fabric such that the shed and the beating of the weft can be repeated.

In one form, the first and second axes are demountable to favor the mounting of the axis or mandrel 7 of the feed system Feed 2 for the drawing of the loop 10.

In one form represented in FIG. 1, the system for maintaining the weaving point is duplicated for each feed system as the first feed system Feed 1 which includes a first maintaining system of the weaving point 71 and as the second feed system Feed 2 which includes a second maintaining system of the weaving point 70, already described. The first and second systems for maintaining the weaving points are analogous. In particular, when the width of the loop 10 is different from that of the lower sub-group 11 of layers, the lengths of the first and second axes of the first system for maintaining the position of the weaving point 71, being on the entire width of the sub-group 11 of fabric layers, are different from those of the first and second axes of the second system for maintaining the position of the weaving point 70 already described.

In FIG. 2, there is represented a portion of a weaving loom according to one form of the present disclosure. The represented portion includes the feed mechanisms or the primary and secondary stretching systems.

In the form of FIG. 2, the primary stretching system 28, 29 mainly includes a horizontal plate intended for receiving the multi-layer fabric which is being woven. The secondary stretching system 21 presents an inclined table disposed above the horizontal plate of the primary stretching system. Except for their relative inclination, the primary and secondary stretching systems are substantially identical and the secondary stretching system 21 will be described. It presents two parallel rails 22, 23 on which a driving carriage 26 slides mounted on pads 24 and 25 engaged on the parallel rails 22, 23. The driving force of the driving carriage 26 is identical to feed Feed 2 described in FIG. 1. The fabric of the aperture or pocket 10, 13 is intended to be stretched under the action of the driving carriage 26 which is connected to the cables 9 bonded to the mandrel 7 inserted into the pocket which is being woven as described in FIG. 1.

Similarly, in the primary stretching system 28, 29, the driving carriage 28 of FIG. 2 is attached to the clamping system 4 of FIG. 1 by the suitable bars 5 of FIG. 1 so that the driving force 29 of FIG. 2 is applied to the fabric which is being woven in the horizontal direction according to the feed Feed 1 described using FIG. 1.

The wrap yarns and weft yarns supply mechanisms upstream of the primary and secondary stretching systems are not represented.

The multi-feed weaving loom of the present disclosure includes at least one plate 21 reserved for the weaving of at least one aperture. A feed system is therefore reserved to realize a primary aperture and/or at least an inner aperture within the primary aperture. Each of these weaving plates of apertures presents at a determined inclination relative to the plate 28, 29 reserved to the weaving of the multi-layer fabric. The weaving plate of the aperture is disposed so that its inclination is measured between the directions 27, 29 of the feeds of the feed systems Feed 1, Feed 2 respectively of said at least one plate 21 of the weaving of the aperture and of the plate 28, 29 of the multi-layer fabric weaving.

In one form, it is noted that the weaving method of an apertured fabric forming a transverse pocket or tube in the weft direction mainly includes the following steps:

E1: a first step of forming the base fabric including a determined number of layers presenting a determined weave;

E2: a second step of forming a loop or an aperture by debonding between the upper layers and a lower sub-group of layers of the base fabric;

E3: a third step of forming the fabric of the loop or the aperture by overconsumption of wrap yarns; and

E4: a fourth step of closing the loop or the aperture by bonding 14 from the end of the weaving of the loop or the aperture 10, 13 to the lower sub-group of the base fabric layers. If necessary, the weaving of the single multi-layer fabric, identical or different from the single multi-layer fabric of the start of the weaving and tight in the clamping system 4, 5 which applies the feed Feed 1 is resumed beyond the point of the bonding operation 14 of the aperture or the pocket 10, 13.

It is understood that the designation of the upper layers or of the lower sub-groups is realized with reference to the example of form of the FIG. 1. It is possible to return over the fabric by thereby placing the formation of the loop or the aperture on the lower face of the multi-layer fabric. In another form of a weaving loom of the present disclosure, an additional feed system is disposed below the main feed system as the feed system Feed 1 (FIG. 1). To realize apertures on the upper face of the multi-layer fabric, it is thus provided an upper feed system and to realize apertures on the lower face of the multi-layer fabric, there is provided a lower feed system, analogous to the upper feed system, but independently controlled. The upper and lower feed systems are disposed on either side of the main feed system.

The method of the present disclosure allows to realize successively several apertures or pockets in the longitudinal direction of the weaving, or that of the feed Feed 1. Such a successive aperture will be formed beyond the bonding point 14 of the first aperture, and in another form may be beyond a resuming of formation of the initial multi-layer fabric. The number of successive apertures or pockets as the aperture 10, 13, is not limited.

The method of the present disclosure also allows to realize one or several aperture(s) or pocket(s) on an aperture or pocket 10, 13 which is being formed. The advantage of such a method is to allow realizing several apertures on each other without requiring draping, stitching additional operation or otherwise. As evoked above, several feed systems with independent controls are therefore disposed in addition to the main feed system, which provides the feed of the base multi-layer fabric.

In the case of a weaving method of a fabric with several simultaneous apertures, the weaving loom of the present disclosure includes at least two feed systems such as the feed systems Feed 1 and Feed 2 described using FIG. 1 and FIG. 2. Particularly, the weaving loom of the form of FIG. 2 is therefore completed by one or several inclined plate(s) additional to the inclined plate 21-27, each inclined plate including at least one feed system associated with its own control.

In FIG. 3, there is represented five examples from (a) to (e) of realizing apertures or loops or pockets. On each example, the right and the left portions of the aperture(s) correspond to layers or sub-groups of layers of a multi-layer fabric formed during the step (a) (FIG. 1) or at the end of the step (e) (FIG. 1). Therefore, the various layers or sub-groups of layers in these areas are joined by wrap yarns according determined weaves. They are instead as it has been described debonded in at the step (b) (FIG. 1) or bonded at the start of the step (e).

In the example (a) of FIG. 3, an aperture or vertical axis pocket 32 forms a debonded area 31 between a lower sub-group of layers of the multi-layer fabric, this sub-group assembling three layers represented at the bonded or debonded drawing, and an upper sub-group of layers of the multi-layer fabric, this sub-group also including three layers represented in the drawing.

In the form of the example (a), the three layers of each sub-group are bonded together according to defined weaves, in the aperture or the loop area.

In the example (b) of FIG. 3, three inner apertures within each other formed of one or several layer(s) of fabric and fully or partially debonded, are formed on the axis 33 above a lower sub-group of three bonded layers. Each inner aperture presents a growing length thus reaching three different heights H1, H2, and H3. Each aperture is mono-layer. In another form, the aperture is a multi-layer of fully or partially bonded layers. In other forms, each inner aperture or the outer aperture of height H3 is woven into a sub-group of bonded layers. The realization is carried out using three bonded feeds, the first feed being common to the three apertures, then stopped for the inner aperture of height H1.

The following feed drives the two outermost apertures until the height H2 and finally, the third feed then drives until the height H3 the only outermost aperture.

In the example (c) of FIG. 3, two apertures 33 and 34 are opposed on an axis 36 around a layer or sub-group of central bonded layers 35. The two opposed apertures 33 and 34 present in the example two bonded layers or not. In this example of form, a main feed system, surrounded by an upper feed system and a lower feed system are disposed on the weaving loom which therefore includes three feed systems with their respective controls.

In the example (d) of FIG. 3, the upper side of a layer or sub-group of central layers is carrying two apertures 37 and 38 the two axes of which are distant by a length L1 while the lower side is carrying a third aperture 39 disposed between the axes of the two apertures 37 and 38 at a distance L2 from the axis of the aperture 37. In the example of form, the aperture 37 presents an inner aperture (without reference number) while the apertures 38 and 39 include a plurality of bonded layers (two without reference number in the drawing). The indicated layers in FIG. 3 are given by way of examples. They can be multiplied or associated into multi-layer units, with or without boded or debonded portions.

In the example (e) of FIG. 3, a first aperture 41 is disposed with two debonded layers or sub-groups. On the same axis 42 as this first aperture 41, a second aperture 40 is formed, constituted of two layers or sub-groups of bonded layers. During the stretching of the second aperture 40, the first layer or sub-group disposed within the second aperture 40, is debonded from the second layer or sub-group of the outer layers, which therefore receives its own stretching to form a third aperture 43 of axis 44 different from the axis 42 of the first and second apertures 41 and 40.

The waving loom of the present disclosure to realize successive apertures on the upper face, respectively lower of the fabric, includes only one feed system additional to the main feed system. To realize integrated and/or inner apertures, an additional feed system for each aperture. As a result, the weaving loom of the present disclosure should include as many additional feed systems as integrated and/or inner apertures in addition to the main feed system. To realize apertures on the lower face of the fabric, at least one additional feed system is disposed under the main feed system. If several integrated and/or inner apertures are provided for the lower face, their number imposes an equal number of additional feed systems as with the aforementioned realization of integrated and/or inner apertures of the upper face described above.

In FIGS. 4 to 7, four wrap planes of an example of form of a weaving at only one aperture 52, are represented. The aperture 52 is limited between two weft planes 50 and 51. In the drawing of the four figures, the unitary multi-layer fabric is found left of the plane 50 and right to the plane 51. It is composed in the example of seven layers of weft yarns referenced from N1 to N7 aligned by level. The first weft yarn of the upper level N7 is referenced 53. The lower sub-group of layers on which the aperture is woven includes the layers N1 to N4. They are bonded by weft yarns which surround a weft out of two of two levels respectively N1, N2 and N3, N4 on the wrap plane of FIG. 4. In the following wrap plane, represented in FIG. 5, the level N1 may be occupied by only one wrap yarn, while a warp yarn bonds in pairs the weft yarns of two following levels N2 and N3. The last level N4 of the lower sub-group is in turn bonded to the following layer N5 so that the lower sub-group of the layers N1 to N4 is bonded to the upper layers which form the aperture 52 between the planes 50 and 51.

In FIG. 6, the wrap plane following that of FIG. 5, the weave of the lower sub-group N1 to N4 resumes the shape of that of FIG. 4. In FIG. 7 which represents the fourth wrap plane, the situation is similar to that of FIG. 5. However, it is noted that the level N4 between the planes 50 and 51 may not be bonded by the warp yarn with the level N5 which, belonging to the weaving of the aperture 52 is stretched upward and debonded from the lower sub-group N1 to N4, by the action of its own stretching system 7-8 (FIG. 1) or 21 (FIG. 2).

To realize the weave of the weaving of the aperture 52, beyond the planes 50 and 51, a bonding of the three layers N5 to N7 is realized using at least two series of warp yarns. Playing with an alternation of a wrap plane out of two, the layers N6 and N7 are bonded together by the wrap yarns of successive planes 54 (FIG. 4), 56 (FIG. 5), 59 (FIG. 6) and 63 (FIG. 7), while the layers N6 and N5 are bonded together by the warp yarns of the successive planes 55 (FIG. 4); 57 (FIG. 5), 60 (FIG. 6) and 64 (FIG. 7).

The weft yarns which are concerned with the interlacing of the warp yarns in three layers N5, N6 and N7 which constitute the weaving of the aperture 52 are not detailed, but it can be observed in FIGS. 4 to 7 that the three layers are sufficiently bonded together.

The weaving method and the weaving loom of the present disclosure allow to produce performs made of multi-layer fabric of different weaves presenting relief over-thicknesses in the form of apertures or pockets above, below or on either side of a sub-group of central layers. It is thus possible to produce reinforcement composite parts with “U”, “T” shapes, rails, hinges and the like. In one form, it is provided to dispose one or several insert(s) and/or the insertion of foam or honeycomb structures within the aperture or the formed loop.

The composite material parts to which the woven preforms of the present disclosure are intended, are manufactured by injecting an injection-polymerizable material and include:

monolithic or “sandwich” type self-stiffened panels: the woven apertured area on the woven preform according to the present disclosure is used to realize a stiffener and/or a clevis and/or to include a stiffener of the “omega”, hollow “omega”, or filled with foam or honeycomb structures type, a corner-flange pair, a “T” stiffener, etc.;

parts of monolithic structure as a frame of a nacelle thrust reverser of an aircraft turbojet engine, a beam, in which the produced area on the aperture(s) of the preform is calculated as stiffener and/or as a clevis and/or as a composite rail; and

any part made of composite material based on an apertured weaving perform according to the present disclosure and calculated for geometrical and/or stiffening and/or mechanical forces passage constraints.

The present disclosure finds its application particularly in the field of manufacture of composite materials, composed with the polymerizable resin and fabrics manufactured in accordance with what precedes. Such parts are used in the aeronautics, and in particular in the composite panels for the aircraft turbojet engine nacelles.

The present disclosure applies irrespective of the type of weaving weave, irrespective of the nature, in particular carbon, glass or Kevlar, and of the type and size of the yarns used.

Claims

1. A weaving loom of a kind including a system for inserting weft yarns into a plurality of layers and a system for inserting and sequencing wrap yarns so as to produce a determined multi-layer weave fabric, wherein the weaving loom comprises at least two feed systems controlled in speed and traction force so that, at least locally, a portion of the multi-layer weave fabric is driven by its own feed mechanism at a different speed from at least one other portion of the multi-layer weave fabric so as to produce at least one aperture on the multi-layer weave fabric.

2. The weaving loom according to claim 1, wherein at least one of said at least two feed systems comprises a system for gripping the multi-layer weave fabric and driving at least outside weaving periods of apertures.

3. The weaving loom according to claim 1, wherein at least one of said at least two feed systems comprises a mandrel for stretching a loop which is being formed on at least one layer or group of layers of the multi-layer weave fabric after debonding.

4. The weaving loom according to claim 2, wherein the weaving loom comprises a plate reserved for the multi-layer weave fabric and the plate is configured to carry a driving carriage of said at least one of said at least two feed systems for gripping the multi-layer weave fabric, and another plate reserved for weaving at least one aperture and which carries a driving carriage of said at least one of said two feed systems for stretching a loop which is being formed on at least one layer or group of layers of the multi-layer weave fabric after debonding.

5. The weaving loom according to claim 5, wherein said another plate reserved for weaving at least one aperture presents a determined inclination relative to the plate reserved for the weaving the multi-layer weave fabric and is disposed such that the inclination is measured between directions of the feeds of said at least one of said at least two feed systems (Feed 1, Feed 2) respectively of said at least one plate, of weaving the aperture and the plate of weaving of the multi-layer weave fabric.

6. The weaving loom according to claim 1, wherein the weaving loom comprises at least one system for maintaining a position of a weaving point associated with at least one of said feed systems (Feed 1, Feed 2) to maintain a height of the weaving point at a start of the fabric, downstream of an insertion region of weft yarns and of an associated shed, such that the shed and the beating of the weft are repeated.

7. The weaving loom according to claim 6, wherein the system for maintaining the position of the weaving point comprises first and second elongated axes on a width of the fabric on either side of surfaces of fabric downstream of the weaving point.

8. A weaving method using the weaving loom according to claim 1, comprising: a step (a) to carry out a start of a multi-layer weave fabric under a determined feed (Feed 1);a step (b) to carry out debonding of at least one layer of the multi-layer weave fabric with stop or slowing down of the feed of the weaving (Feed 1) of the multi-layer fabric;steps (c) and (d) of weaving according to a determined weave of a loop by overconsumption of wrap yarns and stretching at least one debonded layer of the multi-layer fabric under a determined feed (Feed 2) of a determined loop length greater than that of remaining multi-layer weave fabric; anda step (e) of closing the woven loop by bonding.

9. The method according to claim 8, wherein the method is repeated along the multi-layer weave fabric so as to form several successive apertures.

10. The method according to claim 8, wherein the method is repeated on at least one layer of at least one aperture which is being woven so as to form several inner apertures and/or several apertures of different directions.

11. An apertured fabric realized according to the method according to claim 8, wherein the aperture fabric is configured to realize woven preforms to manufacture mechanical parts by injecting an injection-polymerizable material.

12. The apertured fabric according to claim 11, wherein the apertured fabric is configured to realized woven preforms to manufacture monolithic or sandwich type self-stiffened panels, in which at least one woven apertured area on the preform is used to realize a stiffener and/or a clevis and/or to include a stiffener of a hollow “omega” or filled with foam or honeycomb structure type, a corner-flange pair, or a “T” stiffener.

13. The apertured fabric according to claim 11, wherein the apertured fabric is configured to realized woven preforms to manufacture parts of monolithic structures as a frame of a nacelle thrust reverser of an aircraft turbojet engine, or a beam, in which a produced area on the aperture(s) of the preform is calculated as a stiffener and/or as a clevis and/or a composite rail.

14. The apertured fabric according to claim 11, wherein the apertured fabric is configured to realized woven preforms to manufacture a part made of composite material based on an apertured weaving perform and calculated for geometric and/or stiffening and/or mechanical forces passage constraints.